Advances in protein and DNA microarrays have enabled dramatic increases in throughput and equipment standardization has made these techniques more commonplace. High density, high throughput microarrays reduce the cost of research and development in drug discovery and basic science by decreasing reagent volumes and increasing the number of experiments per plate. Missing from this miniaturization, however, are cell culture microarrays. Existing low well count cell culture plates require greater volumes of precious drug formulations for permeability assays and more plates are required to complete a series of experiments. These same factors increase the cost of parallelized cellular experimentation in basic science such as screening stem cell culture differentiation conditions. In this proposal we will test the feasibility of using a new class of ultrathin nanoporous membrane to enable miniaturization of cell culture screening for high throughout drug permeability and co-culture studies. At the limit we will enable single cell screening to study phenotypic and behavioral variations in cell populations in response to stimuli, drug treatments or co-culture environments. In the first Aim of this work, we will fabricate microarray-scale cell culture arrays using porous nanocrystalline silicon (pnc-Si). We will confirm these devices and size format promote healthy growth of primary human umbilical vein endothelial cells by comparing cytotoxicity and growth curve measurements against larger conventional cell inserts. To test feasibility as a high throughout platform for single cell and co-culture screening, we will develop a microarray of wells on pnc-Si. Our approach is novel because we will be the first to offer a membranesupported microarray that enables study variations in populations of cancer cells, stem cells as well as primary cell response to drug treatment in a co-culture environment. In Phase II we will focus on drug screening and stem cell differentiation with the goal of developing an automated cell dispensing and fluorescent image analysis system. In both cases we will also pursue enlarged microarrays (>100 microns) with degradable membrane supports, which will permit the growth a small islands of stratified tissue. Successful completion of Phase I will enable the launch of a live imaging research tool for small-scale cell co-culture. Within 6 months of completing Phase II, we will introduce a 384-window microarray system with >105 wells. HEALTH RELEVANCE: SiMPore's pnc-Si membranes are a breakthrough technology 1,000x thinner than conventional and other nanoporous membranes, with permeability more than 100 times greater. These characteristics enable miniaturization of conventional cell culture and the development of high---throughput screens for single cell co-culture research including stem cell differentiation, cancer cell response to drugs and tissue engineering.